This nonlinear inequality can be seen as the result of an optimization over a family of linear inequalities [1]}
\( \Delta ^2( O_1) &\ge 4 \sup _{t\in \mathbb {R}} \left[ \left|t\right| \left\langle B \right\rangle  - t^2 \Delta ^2( O_2) \right] \\&= - 4 \inf _{t\in \mathbb {R}} \left[ t^2 \Delta ^2( O_2) - \left|t\right| \left\langle B \right\rangle  \right] \;, \) 
